Liquid pressure remote control system



Feb. 13, 1940.

E. c. s. CL ENCH LIQUID PRESSURE REMOTE CONTROL SYSTEM Filed March s, 1938 2 SheeFs-Sheet 1 Feb. 13, 1940. 5 LENC 2,190,257

LIQIjID PRESSURE REMOTE CONTROL SYSTEM Filed March 3, 1938 2 Sheets-Sheet 2 liars/e301 a I' (257%1zc4 Patented Feb; 13, 1940 UNITED STATES PATENT OFFICE 2,190,257 mourn ranssuaa REMOTE comm] srs'ram Application March 3, 1938, Serial No. 193,790

In Great Britain March 20, 1937 v 8 Claims.

This invention relates to liquid pressure remote controlsystems, and it has for its primary object to provide improvements in the known form of remote control system utilising a single pipe-line a connection between the transmitter unit and the motor unit. Such systems are, of course, commonly used for the hydraulic actuation of brakes and in other instances where the transmitter and motor units automatically return to a predetermined off position when the pedal, lever or other actuating member ceases to be restrained or operated. The improvements according to the present invention enable a very simple construction of single-acting liquid pressure remote control system to be produced for purposes where the actuating member of the transmitter unit must remain of its own accord at any position in which it may be set within its range of operative movement.

20 In a liquid pressure remote control system comprising a transmitter cylinder and piston having actuating means, a motor cylinder and piston, a single pipe line connecting said cylinders, and a return spring adapted to move the motor piston 25 forward as the transmitter piston is retracted, the

present invention is characterised by the provision of locking means which are automatically rendered operative by the action of letting go the actuating. means.

30 The invention further provides a liquid pressure remote control system comprising a transmitter cylinder and piston having actuating means, a motor cylinder and piston, a single pipe line connecting said cylinders and a return spring 35 adapted to movethe motor piston forward as the transmitter piston is retracted, a lost motion device beingprovided between the actuating means and the transmitter piston, and an automatic locking device for said piston being released by the movement of the actuating means in taking up the lost motion at the commencement'of a resetting operation. The locking device is preferably effectual to prevent movement of the transmitter piston in both directions except, of course, 45 under the influence of the actuating means, while the transmitter piston can conveniently be acted upon by a spring which tends to move it forward and thus opposethe action of the spring of the motor piston with a view to rendering the sys- 50 tem easier to operate. A hydraulic accumulator device is preferably provided to receive any working liquid expelled from the system due to a rise of temperature while the motor piston is in its fully retracted position, since the locking device 5 preventsthe transmitter piston from responding (Cl. Gil-54.5)

to such an increase in volume. The motor piston, in reaching'its extreme retracted position, may place the pipe line in communication with the hydraulic accumulator device by way of a nonreturn valve, the working space of the accumu- 5 .lator preferably being in permanent communication with the pipe line through another non-return valve whereby liquid forced into the accumulator device while the motor piston is in its fully retracted position can be discharged to the pipe line when the pressure in the latter falls, irrespective of the position of the motor piston.

' The locking of the transmitter piston can conveniently be eifected by a roller or equivalent member which is resiliently held between a pair of converging surfaces, one of which latter is fixed while the other is movable in unison with the transmitter piston. Thus, the transmitter piston may be moved by a pivoted member which carries one of the pair of converging surfaces, the other of said surfaces comprising an arcuate track arranged concentrically with regard to the pivotal axis of the pivoted member. The actuatin means may carry a releasing memberwhich urges the roller or equivalent out of engagement with the converging surfaces so as to release the looking means and may comprise a handle which is mounted for arcuate movement'about the same axis as the pivoted member, with which latter it is connected by a lost motion device. 0

The invention is illustrated in the accompanying drawings in which Figure 1 is a sectional elevation of the preferred transmitter and motor units; 1 Figure 2 is a sectional side elevation of the transmitter unit taken on the line 2-=-2 of Figure 1;

Figure 3 is a fragmentary sectional plan taken on the line 3-3 of Figure 1;

Figures 4 and 5 are enlarged diagrammatic 40 views of, the locking device in its locked and unlocked positions respectively; and

Figure 6 is a sectional side elevation through the motor unit taken on the line 6-6 of Figure 1.

The remote control system illustrated, which is primarily intended for regulating the throttle of a marine engine but which can obviously be used for many other purposes, comprises a transmitter unit indicated generally at A and a motor unit B, these being connected together by a single pipe line Ill 'adapted for the transmission or liquid.- under pressure.

A casing H forms the body of'thetran'smitter unit A, and carries a casting comprising a combined reservoir 12 and tr nsmitter cylinder ll.

A transmitter piston H, which is substantially tubular in form except for a web I5, is slidably mounted within the cylinder l3 and is actuated by means of a connecting rod l6 pivoted to a bracket l1 secured to the Web |5. At its other end the connecting rod I6 is bifurcated, as will be seen more clearly in Figure 2, and is connected by means of a pin Hi to a pivoted rocking member I9. The latter is freely rotatable upon a fixed tubular spindle 20 carried by the casing H and comprises a pair of side plates 2| and 22, both of which latter are extended downwardly as will be seen in Figures 1 and 2 so as to carry a ,pin 23, by which the pivoted member l9 is connected with a rod 24. This is slidably mounted within a tube 25 abutting against a plate 21 in the casing through the medium of a ball 26, said tube 25 and rod 24 being fitted with radial flanges 28 and 29 respectively for the accommodation of a pair of coiled compression springs 30 and 3|.

The plate 2| is also extended towards the left as indicated at 2|a in Figures 1 and 3, and carries a block 32 which is used for locking the pivoted member l8 and consequently the transmitter piston M at any position or setting within itsrange of movement. A curved track 33 is carried bythe casing I and has an internal surface 34 which is concentric with the spindle 20, but the block 32 has its adjacent surface 35 shaped to a greater curvature than the surface 34 or else is cut away at its outer corners so that the surfaces 34 and 35 converge in a direction towards the centre radial line of the block 32, as will be seen more clearly in Figures 4 and 5.

A pair of rollers 33 and 31 are carried upon the block 32 by laminated spring fingers 38 and are urged thereby into the space between the converging surfaces 34 and 35 of the track 33 and block 32 respectively. This, of course, produces a locking action and normally prevents movement of the block 32 in either direction, since such movement causes one or other of the rollers 36 and 31 to become more firmly jammed between the said converging surfaces 34 and 35.

In order to reset the transmitter piston H i. e. to change its setting or position within its range of movement, a handle 40 extends through an arcuate slot 4| in the rounded end of the casing II and is formed at its lower extremity with a boss 42 which is freely rotatable upon the centre portion 43 of the pivoted member I9. The boss 42 has a lug 44 which is formed with a hole 41 embracing the pin l8 with a relatively large amount of clearance. The boss 42 is also extended as indicated at 45 in Figures 1 and 3 and carries an L-shaped releasing member 46, the extremity of which is positioned between the two rollers 36 and 31 as will be seen more clearly in Figures 4 and 5. Thus, when the handle 4|] is moved in either direction the initial movement which takes up the play between the hole 41 and the pin 8 also causes the releasing member 46 to press one or other of the rollers 36 and -31 out of engagement with the converging surfaces 34 and 35 so that, when the lost motion between the hole 41 and pin 8 has been taken 'up, any further movement imparted to the han- The reservoir |2 normally contains a supply of liquid which is inserted by removing a filler cap 58, and the lower part of said reservoir extends completely round the transmitter piston H in the form of an annular passage 5| as seen in Figure 1. Thus, when the transmitter piston I4 is in its completely retracted position a number of small holes 52 in the forward end of the piston are brought into register with the passage 5|, thus placing the pipe line l3 automatically into communication with the interior of the reservoir l2. Packing rings 53 and 54 prevent leakage of liquid along the piston, and a bleed plug 55 is incorporated in the cylinder l3 for the purpose of removing air when the system i's being filled with liquid.

In the motor unit B a casing 38 is fitted with a motor cylinder 6|-.having a slidably mounted motor piston 62 which is identical in construction to the transmitter piston 4. This piston is coupled by a connecting rod 53 with a pivoted lever 64 which comprises two plates 65 and 88, as will be seen in Figure 6, and is securely carried by a spindle 61. Externally of the casing this spindle is secured to an arm 88, which is mechanically connected to the throttle (not shown) or any other'device which it is desired to operate from a distance. For efl'ecting the forward movement of the motor piston 82 the lower end of the lever 84 is acted upon by a pair of coiled compression springs 69 and 18 which are supported by a telescopic link comprising a pin 1| and tube 12 corresponding in construction to the parts 24 and 25 of the transmitter unit A. The motor cylinder 8| carries packing rings 13 and 14 and is formed between these with an annular passage 15. This, as shown in Figure l, communicates with the pipe line through holes 18 in the piston when the latter is in its fully retracted position. Formed in one with the motorcylinder 6| is a hydraulic accumulator device comprising a cylinder bore 11 accommodating an accumulator piston 18 which is normally forced to its end position as shown by means of a coiled compression spring 13. A slight projection 88 is formed on the piston 18 so as to ensure that pressure liquid passing from the annular passage 15 through a non-return ball valve 8| can act upon substantially the whole area of the piston 18. A passage 82 leads from the space 83 in front of the piston 18, past a non-return ball valve 84 and communicates with the pipe line In by way of a passage 85, so that whenever the space 83 contains liquid at a pressure greater than that in the pipe line said liquid can be discharged through the non-retum valve 84. The purpose of the accumulator device 11, 18 is to avoid an excessive rise of pressure in the event of the volume of the working liquid increasing (due for example to a rise in temperature) while the parts are in the position shown in Figure 1. It will be appreciated that under these conditions the motor piston 62 is at theend of its travel and cannot move any further since the telescopic link 1|, 12 is'fully shortened. If, therefore, an expansion occurs in the working liquid corresponding to the expansion is forced past the ball valve ll in the motor cylinder I and finds accommodation within the space It by compressing the spring 19. When at some latertime the pressure in the pipe line ll decreases, due for example to cooling, then the liquid from the space It is automatically. returned by the piston ll through the passages l2 and ii.

In the improved remote control system the primary iunction of the compression spring assembly 69, I is to move the motor piston 62 in a forward direction as soon as working liquid is withdrawn through the pipe line ll owing to the operation of the handle 40 to retractthe transmitter piston ll. Thus. the springassembly 69, III creates and maintains apressure in the working liquid exceptwhen the motor piston 2 has reached its extreme forward position where it comes into mechanical contact with the end of the motor cylinder 6|. When this occurs. however, the transmitter piston II is retracted as far as possible and the holes 52 are in communication with the interior of the reservoir I! so that the whole system is allowed to breathe" at this particular setting, thus ensuring that the pipe line In and the working spaces of the cylinders l3 and H are full of liquid at atmospheric pressure. In the case of a remote control for working an engine throttle this breathing and rephasing position preferably corresponds to theoif position of the throttle. The spring assembly 30, 3| in the transmitter unit cannot consistently produce liquid pressure in the system owing to the action of the locking device. but is incorporated to counteract the eiiect of the spring assembly in the motor unit and thus considerably reduce the amount of eifort which is required to operate the lever ll.

The springs employed-in the transmitter and receiver units may be made so as to have variable rates in order to. compensate substantially for the changein the moment which they exert about the pivots of the respective lever arms due to the "changes in the angular positions of the latter. This may be done by making the coils of the spring of varying stillness and/or pitch so that a predetermined portion will first become coil-bound, and the rate of the spring will thus be increased.

What I claim is: 1. A liquid pressure remote control system comprising a transmitter cylinder and piston, a,

motor cylinder and piston, a spring urging said motor piston towards its fully advanced position, a single pipeline connecting the transmitter cylinder with the motor cylinder, a rocking member connected with the transmitter piston, angularly movable actuating means connected operatively with the rocking member by a lost motion connection, and locking means for preventing movement of the transmitter piston, except h under the influence of the actuating means, said locking means comprising a pair oi converging surfaces, one upon the rocking member and one fixed in relation to the transmitter cylinder, said fixed surface being concentric with theaxis upon which the rocking member moves, a wed ging member arranged t'ojam between said surfaces, resilient means urging said wedging member towards its jammed position, and means to disengage the wedging member from the surfaces during the movement reguired to take up the lost member connected with the transmitter piston,.

angularly movable actuating means connected operatively with the 'rocking member by a lost motion connection and. arranged to move about the same axis as the rocking member, and locking means for preventing movement of the transmitter piston, except under the influence of the actuating means, said-=.locking means comprising a pair 0! converging surfaces, one upon the rocking member and one fixed in relation to the transmitter cylinder, said fixed surface being concentric with the axis upon which the rocking member moves, a rollerzarranged to jam between said surfaces, resilient means urging said roller towards its jammed position, and means uponthe actuating member arranged to disengage, the roller from the surfaces'during the movement required to take up the lost motion between the actuating member and the rocking member.

3. A liquid pressure, remote control system comprising a transmitter cylinder and piston, a

' motor cylinder and piston, a spring urging said .rocking member to retract the transmitter pis ton and locking means for preventing movement of the transmitter piston, except under the influence of the actuating means, said locking,

means comprising a pair of surfaces arranged side by side, one upon the rocking member and one. fixed in relation to the transmitter cylinder, said fixed surface beingconcentric with the axis upon which the rocking member moves and the other being shaped so that both its end portions converge in relation to the said concentric surface, a pair of rollers arranged to jam in opposite directions between the said surfaces, resilient means urging said rollers towards their jammed positions, and means upon the actuating member arranged to disengage either one of the rollers from the surfaces during the movement required to take up the lost motion between said actuating member and the rocking member.

4. A liquid pressure remote control system comprising a transmitter cylinder and piston, a motor'eylinder and piston. a spring urging said motor piston towards its fully advanced position, a single pipe line connecting the transmitter cylinder with the motor cylinder, a rocking member connected with the transmitter piston, angularly movable actuating means connected operati'vely with the rocking member by a lost motion connection and arranged to move about the same axis as the rocking and locking means for preventing movement of the transmitter piston, except under the influence of the actuating means, said locking means comprising an arcuate concave surface secured rigidlyin relation to the transmitter cylinder and disposed concentrically with the mounting axis at the rocking member.

an arm formed on said rocking member and directed towards said arcuate surface, the extremity of said arm being curved to a relatively small radius so that its center part lies nearer to the arcuate surface than its end parts, rollers interposed between said end parts and the arcuate surface, resilient tongues supporting said rollers and urging them towards one another so as to lock the rocking member against movement in both directions, and disposed between said rollers a projection which is secured to the actuating means and which pushes either one of the rollers out of engagement with the two surfaces while said actuating member moves to take up the lost motion between it and the rocking member.

5. A liquid pressure remote control system comprising a transmitter cylinder and a piston therein, actuating means for the piston, a motor cylinder and piston therein, a single pipe line connecting said cylinders, a return spring to move the motor piston forward as the transmitter piston is retracted, a lost motion device between the actuating means and the transmitter piston, resilient means urging the actuating meansto a central .position with respect to the lost motion device, an automatic locking device for locking said transmitter piston against move ment in'both directions, the movement of the actuating means in either direction when taking up the lost motion at the commencement of a resetting operation releasing the automatic looking device, said locking device including opposed members each of which is resiliently held between a pair of converging surfaces, one of said surfaces being fixed and the other movable inunison with'the transmitter piston.

6. A liquidpressure remote control system comprising a transmitter cylinder and piston. actuating means for the piston, a motor cylinder and piston, a single pipe line connecting said cylinders and a return spring adapted to move the motor piston forward as the transmitter piston is retracted, a lost motion device between the actuating means and the transmitter piston, an automatic locking device for normally preventing said piston being moved by the liquid in the direction in which it is moved by the actuating means, the movement of the actuating means in taking up the lost motion at the commencement of a resetting operation releasing the automatic locking device, said locking device including a roller or equivalent member which is resiliently held between a pair of converging surfaces,

comprising an arcuate track arranged concentrically with regard to the pivotal axis of the pivoted member.

7. A liquid pressure remote control system comprising a transmitter cylinder and piston, actuating means for the piston, a motor cylinder and piston, a single pipe line connecting said cylinders and a return spring adapted to move the motor piston forward as the transmitter piston is retracted, a lost motion device between the actuating means and the'transmitter piston, an automatic locking device for normally preventing said piston being moved by the liquid in the direction in which it is moved by the actuating means, the movement of the actuating means in taking up the lost motion at the commencement of a resetting operation releasing the automatic locking device, said locking device including a roller or equivalent member which is resiliently held between a pair of converging surfaces, one of said surfaces being fixed and the other being movable in unison with the transmitter piston, the actuating means carrying a releasing member which urges the roller or equivalent out of engagement with the converging surfaces so as to release the locking means, the actuating means comprising a handle mounted for arcuate move ment upon the same agris as the pivoted member, being connected with said member by a lost motion device.

8. A liquid pressure remote control system comprising a transmitter cylinder and piston, actuating means for the piston, a-motor cylinder and piston, a single pipe line connecting said cylinders and a return spring adapted to move the motor piston forward as the transmitter piston is retracted, a lost motion device between the actuating means and the transmitter piston,

- an automatic locking device for normally preventing said piston being moved-by the liquid in the direction in which it is moved by the actuating means, the movement of the actuating means in taking up the lost motion at the commencement of a resetting operation releasing the automatic locking device, said locking device including a roller or equivalent member which is resiliently held between a pair of converging surfaces,

, one of said surfaces being fixed and the other being movable in unison with the transmitter piston, movement being imparted to the transmitter piston by a pivoted member having a pair of substantially diametrically opposed arms, one of which is coupled to the transmitter piston by a connecting rod and the other of which is acted upon by a coiled compression spring.

EDWARD CLAUDE SHAKESPEARE CLENCH. 

